Capacitive Humidity and temperature sensor with I2C

[davedeluxe]

Hi,

I have this sensor:
https://ex-store.de/Kapazitiver-Feuchti ... altausgang
and would like to use it on a Wemos C1.
Unfortunately, I do not know how I must connect it, can someone please help me?

Thanks Dave

[krikk]

interesting sensor, seems to be a variation of this one: https://www.tindie.com/products/miceuz/ ... re-sensor/ (which is supported already)

...but the interface is not exactly the same, should be really easy to adapt my plugin (_P047_i2c-soil-moisture-sensor.ino) to work with your sensor...

the price is also very nice, only shipping to austria (13 EUR) is not nice

[davedeluxe]

Unfortunately I have no experience with writing plugins.
Perhaps you are looking to have a look, I have found the right information about the sensor here:
https://ex-store.de/Kapazitiver-Feuchti ... altausgang

[Ton_vN]

Interesting device, but curious whether (& how much) the 'probe' will have a longer life-span than the cheaper 'probe' which I apply for my setup to measure groundhumidity.
The URL points to a webpage in Dutch (with my experiences and results), but hopefully the text is simple enough to be understandable for non-dutch readers.

[davedeluxe]

I think that the device is not destroyed by corrosion because it is about capacitive measurement and the electrodes are not blank.

[Shardan]

Hello,

it should be differed between some types of humidity and rain sensors.

DC-Driven:
Cheap sensors, usually they have just a comparator (LM293, LM292 or similiar) and a variable resistor to set a threshhold.
Nice for experimenting, but they will corrode away fast. It uses the liquid resistance of soil or rain.
This usually is what you find on eBay, aliexpress around 2$.

AC driven:
Sensor looks same as DC driven but the circuit usually is more complex. They use AC for the sensor this avoiding
the electrolytic corrosion. If a high quality sensor is used it will run quite long. It uses the liquid resistance of soil or rain.
This is the "little grey box" type sensor you will find often for winding up an awning if it starts to rain..
I know some running for > 25 years without issues. Far more expensive then DC-sensor types.

Capacitive:
Capacitive sensors use a sensor that does not get in direct contact with moist or rain at all.
Thus makes it "long life" - as long as the covering of the sensor is intact.
It uses a high frequency oscillator and the sensor is the capacitor part of an oscillating circuit.
Moisture from rain or wet soil moves the resonance frequency of the oscillation circuit away from the
oscillators frequency. This can be detected easily.
Most senitive but most complex circuit and consequently most expensive too.

Regards
Shardan

[Ton_vN]

Shardan is right that the application of AC or capacitive measurement surely extends lifetime, but I am more thinking related to the aspect that the metallic parts of the sensor's probe anyway have constant contact with wet/humid soil and that the electronics are located quite near the humid soil (with also risk of emersion).
That is never favourable: not without reason for the tindy-device it is advised to put an extra cover over the sensor.

Question alternatively formulated:
what is the expected lifetime of this device if applied without or with an extra protection?

Further search reveals comparable concepts with analogue interface or with RS485-interface:
see https://www.letscontrolit.com/forum/vie ... 081#p17081